The present invention relates to a fuel injection control device configured to switch an injection mode between direct injection and port injection.
During the cold time of an internal combustion engine, a failure in fuel vaporization easily occurs and fuel easily adheres to a wall surface. Consequently, some of injected fuel does not make any contribution to combustion. For this reason, it is common to increase a fuel injection amount during such cold time of an internal combustion engine. Meanwhile, as described in Japanese Laid-Open Patent Publication No. 2012-117472, an internal combustion engine has been known that is provided with two different types of fuel injection valves including a port injection valve, which injects fuel into an intake port, and a direct injection valve, which injects fuel into a combustion chamber. In the internal combustion engine, the injection mode is switched such that the injection ratio of the direct injection and the port injection is varied.
The occurrence condition of a failure in fuel vaporization or adhesion of fuel to a wall surface during the cold time depends on the area to which the fuel is injected. For this reason, if both the fuel injection amount in direct injection and the fuel injection amount in port injection are increased in the same manner during the cold time, the amount of fuel that contributes to the actual combustion may be excessive or insufficient.